<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        /* .nav li 权重是 11 */
        .nav li {
            color: red;
        }

        /* .pink 权重是 10   .nav .pink权重是 20*/
        .nav .pink {
            color: pink;
        }
    </style>
</head>

<body>
    <ul class="nav">
        <li class="pink">11111</li>
        <li>22222</li>
        <li>33333</li>
        <li>44444</li>
        <li>55555</li>
    </ul>
</body>

</html>